Worktree paths in git panel, take 2 (#26047)

Modified version of #25950. We still use worktree paths, but repo paths
with a status that lie outside the worktree are not excluded; instead,
we relativize them by adding `..`. This makes the list in the git panel
match what you'd get from running `git status` (with the repo's worktree
root as the working directory).

- [x] Implement + test new unrelativization logic
- [x] ~~When collecting repositories, dedup by .git abs path, so
worktrees can share a repo at the project level~~ dedup repos at the
repository selector layer, with repos coming from larger worktrees being
preferred
- [x] Open single-file worktree with diff when activating a path not in
the worktree

Release Notes:

- N/A

crates/file_finder/src/file_finder.rs

@@ -42,8 +42,8 @@ use ui::{
 };
 use util::{maybe, paths::PathWithPosition, post_inc, ResultExt};
 use workspace::{
-    item::PreviewTabsSettings, notifications::NotifyResultExt, pane, ModalView, SplitDirection,
-    Workspace,
+    item::PreviewTabsSettings, notifications::NotifyResultExt, pane, ModalView, OpenOptions,
+    OpenVisible, SplitDirection, Workspace,
 };
 
 actions!(file_finder, [SelectPrevious, ToggleMenu]);
@@ -1239,7 +1239,10 @@ impl PickerDelegate for FileFinderDelegate {
                                         } else {
                                             workspace.open_abs_path(
                                                 abs_path.to_path_buf(),
-                                                false,
+                                                OpenOptions {
+                                                    visible: Some(OpenVisible::None),
+                                                    ..Default::default()
+                                                },
                                                 window,
                                                 cx,
                                             )

crates/file_finder/src/file_finder_tests.rs

@@ -7,7 +7,7 @@ use menu::{Confirm, SelectNext, SelectPrevious};
 use project::{RemoveOptions, FS_WATCH_LATENCY};
 use serde_json::json;
 use util::path;
-use workspace::{AppState, ToggleFileFinder, Workspace};
+use workspace::{AppState, OpenOptions, ToggleFileFinder, Workspace};
 
 #[ctor::ctor]
 fn init_logger() {
@@ -951,7 +951,10 @@ async fn test_external_files_history(cx: &mut gpui::TestAppContext) {
         .update_in(cx, |workspace, window, cx| {
             workspace.open_abs_path(
                 PathBuf::from(path!("/external-src/test/third.rs")),
-                false,
+                OpenOptions {
+                    visible: Some(OpenVisible::None),
+                    ..Default::default()
+                },
                 window,
                 cx,
             )